it all depends on how the italian teams do in the champions league. if they drop out after the group stages not much would change.
I do not think that the sponsorship deals would improve, because we are pretty good on that already.
i would even say that it could even get worse for us if we are not the only big fish in italy anymore.
sponsoring companies will not magically create more funds to spend on sponsorships just because there are more proper teams in italy, but simply reallocate what the plan to spend on sponsoring, so instead of us getting the biggest offers a sponsor like Nike could say "dear juve, we give you 90millions over 5 years and if you don't take it there is ac milan (that is in CL too) waiting around the corner to take that deal.".